Lock



FIG. 1 is a perspective view of a lock showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a right side elevational view thereof; and,

FIG. 7 is a left side elevational view thereof.

The broken lines which define the bounds of the claimed design, form no part thereof. The broken lines environmental are for illustrative purpose only and form no part of the claimed design. 

The ornamental design for a lock, as shown and described. 